Selective Breeding Reflective Learner Self Manager Team Worker L.O: Understand selective breeding and its associated issues Grade 4: Describe the process of selective breeding and give one example where it has been used. Grade 6: Explain the process of selective breeding and why humans have used it. Explain what inbreeding is, and why it is a problem in dog breeding. Grade 8: Compare and contrast natural and artificial selection. Explain in detail how the variation of alleles in a population is reduced through selective breeding and why this is a problem. Reflective Learner Self Manager Team Worker Effective Participator Independent Enquirer

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Introduction to Selective Breeding Boardworks GCSE Science: Biology Genetic Engineering Introduction to Selective Breeding Selective breeding, or artificial selection, is a process where people try and improve plants and animals by selecting and breeding only those that have desirable characteristics. For example, a farmer might choose the two largest cattle in his herd and breed them together so that the offspring will be even bigger and produce more meat.

Task Independent Enquirer Use the resources to answer the following – look at what your target grade is! Grade 4: Describe the process of selective breeding. Give one example where it has been used. Grade 6: Explain the process of selective breeding and why humans have used it. Explain what inbreeding is, and why it is a problem in dog breeding. Grade 8: Compare and contrast natural and artificial selection. Explain in detail how the variation of alleles in a population is reduced through selective breeding. Explain why this is a problem. Independent Enquirer Resources Video clip AQA text book pages 222 – 223 Resource sheet

Command Words State, give, name, write down - Short answer is required, often it can be answered with a single word, phrase or sentence. Describe - Recall some facts, events or process in an accurate way. For example they may be asked to describe an experiment they have done, or they may need to give an account of what something looked like, or what happened, eg a trend in some data.

Command Words Explain - Make something clear, or state the reasons for something happening (not be a simple list of reasons). Points in the answer must be linked coherently and logically. Suitable linking words could be ‘so’, ‘therefore’, ‘because’, ‘due to’, ‘since’, ‘this means’ or ‘meaning that’. All of the stages/steps in an explanation must be included to gain full marks. Compare - Describe the similarities and/or differences between things, not just write about one.. E.g. ‘compare x with y’, you need to write down something about x compared to y, using comparative words such as ‘better, ‘more than’, ‘less than’, ‘quicker’, ‘more expensive’, ‘on the other hand.’

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GRADE 4 Recap and self assess Selective breeding is breeding together two members of the same species to create an organism with desired characteristics. For example wheat with lots of grain, cows that produce a lot of milk, plants that are resistant to disease, domestic dogs, farm animals with gentle nature, large/brightly coloured/scented flowers

GRADE 6 Recap and self assess Selective breeding is when animals (or plants) with desired features are selected from a mixed population. They are bred together. Offspring with the desired characteristics are selected and bred together. This continues until you have an organism with the desired features. It has been used to progress agriculture and farming. For example breeding dairy cows for milk, chickens for high egg yield, crops that are disease resistant. Inbreeding is when an organism mates with a close relative. Inbreeding results in little variation in the population and is a problem in dogs as some breeds are prone to particular diseases or inherited defects. E.g. epilepsy in boxer dogs, King Charles Spaniels having a brain too big for their skull, pugs struggling to breathe.

GRADE 8 Recap and self assess Natural and artificial selection both involve members of the same species mating to produce offspring. Natural selection is where one organism breed with another organism of their choosing whereas two organisms with desirable characteristics are selected to breed together in artificial selection. Variation of alleles is reduced because only organisms with particular alleles (leading to the desirable characteristics) are allowed to breed. The organisms with alternative alleles do not breed and therefor the alleles are not passed on to subsequent offspring, reducing the variation of that allele in the population. Reduced variation of alleles within a population becomes a problem when environmental conditions change. Those organisms may not be best suited to survive the environmental change and could die out. For example bananas are genetically very similar and are at risk of dying out from new pathogens as none of them are resistant to it.

Team Worker Reflective Learner Exam Question Reflective Learner Fill in your own but work in pairs 5 minutes to complete Peer assess in pink pen using the mark scheme

Selective Breeding Reflective Learner Self Manager Team Worker L.O: Understand selective breeding and its associated issues Grade 4: Describe the process of selective breeding and give one example where it has been used. Grade 6: Explain the process of selective breeding and why humans have used it. Explain what inbreeding is, and why it is a problem in dog breeding. Grade 8: Compare and contrast natural and artificial selection. Explain in detail how the variation of alleles in a population is reduced through selective breeding and why this is a problem. Reflective Learner Self Manager Team Worker Effective Participator Independent Enquirer